Vehicles that use different sources of energy for operating the vehicle are referred to as hybrid vehicles. Hybrid vehicles having one internal combustion engine and at least one electric motor are known. The electrical energy of the electric motor comes from an energy accumulator, e.g., one or a plurality of batteries and/or supercapacitors (“supercaps”). In addition, the vehicle has the possibility of recovering braking energy in the form of electrical energy (recovery). An operating strategy is intended to ensure that the two propulsion engines are operated at the particular optimum and that braking energy arising is recovered for storage with as little loss as possible. The purpose of hybridization is to reduce the consumption of primary fuels compared to conventional vehicles that are operated only with internal combustion engines.
A method for controlling a hybrid vehicle is described in German Patent Application No. DE 101 28 758, the propulsion being provided by a first internal combustion engine and/or an electric motor according to the specification of an operating controller, the percentage contribution of the electric motor drive being controlled as a function of the data pertaining to the travel route communicated to the operating controller, taking into account the charge state of an energy accumulator for electrical energy, the data including altitude information which is used as the basis for controlling the percentage contribution of the electric motor drive, the charge of the energy accumulator not dropping below a minimum level which is defined or definable in the operating controller and is necessary to still ensure basic vehicle functions. The operating controller receives the altitude information from data of a navigation system or of another predictive system.